This invention relates to the field of machines of the vane type rotary motors and pumps; and more particularly to means for sealing the vanes thereof relative to the machine casing as well as the ends of the vane carrying slots of the rotor, against pressure leakages when centrifugal operating forces acting on the vanes are insufficient to maintain them in efficiently sealing contact with the wall surface of the machine casing. The problem of establishing such effective seals between the vanes and the walls of the motor cavity to provide efficient start-up and slow running capabilities for the machine has been a major handicap against usage of such machines, especially in the hoisting machine industry.
Therefore, an object of the present invention is to provide an improved form of pressured fluid powered machine including means by which the vanes of the machine are caused to be in pressure-sealing relation against the cylinder walls even when the rotor thereof is stationary; thereby insuring immediate start-up driving power for the machine as well as smooth torque output at any desired rate of variable speed and thus eliminating delay in achieving full power drive by the machine as well as a smoother operation at slow speeds. Another object is to provide in a machine of the type described vanes of improved configurations whereby an improved pressure sealing arrangement is provided for the vanes vis-a-vis stationary parts of the machine casing; thereby reducing the rate of wear on the operating parts of the machine.
Essentially, then, the present invention provides a hoist powering motor of the pressurized-fluid powered rotary vane type comprising: a casing having a cylindrical inner wall surface; end bells at opposite sides of said casing defining a fluid cavity therein; compressed fluid inlet and outlet ports in one of said bells in open communication with said fluid cavity; a rotor extending between said end bells carried by a drive shaft for rotation about an axis eccentric to said casing inner wall surface; said rotor provided with counterbored end portions adjacent said end bells and a plurality of longitudinally extending radial slots about the periphery thereof, each of said slots having inner portions communicating with said counterbored end portions; a plurality of vane devices slidably carried within said slots having inboard edge portions and outboard edges; a resilient vane lift ring disposed adjacent the inner surface of each of said end bells and located within the confines of each of said counterbored end portions in constant bearing engagement with said vane inboard edge portions to urge said vane outboard edges into contact against said casing inner wall surface; and a resilient seal plate substantially coplanar with each of said lift rings having a circular periphery concentric with said inner surface of said casing fixed with respect to the inner surface of each of said end bells and accommodated within each of said counterbored end portions in close spaced relationship with the inner periphery of each vane lift ring to permit said lift ring to orbit in contact with said vanes without dragging against said seal plates.